Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds real value by making the idempotency concrete — an existing site gains only its missing checks, an existing group is not duplicated — and it discloses the return payload. It does not mention permission or ownership requirements, which would be the remaining gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, zero filler, and the usage condition is front-loaded ahead of the return behavior, dedup semantics and the sibling exclusion. Every sentence carries decision-relevant information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, and the description compensates by stating what is returned. All seven parameters are documented in the schema, the mutation nature is covered by annotations, and the idempotent re-add behavior — the most likely source of agent error — is spelled out.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. The description goes beyond the per-parameter text by explaining how the parameters interact: the site is returned 'with the checks chosen under it, placed in a group if one is named', which tells the agent that site, children and group compose rather than being independent flags.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb and resource — showing one of the user's sites or a group heading on a status page — and explicitly separates itself from page creation by naming plan_status_page. An agent can tell this apart from the create path without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It states the trigger condition ('when the user wants another of their sites, or a group heading, shown on one of their status pages') and an explicit exclusion with the correct alternative ('Not for creating a page: use plan_status_page'). That is when-to-use plus when-not-to-use plus a named alternative.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.